Changes in oxytetracycline resistance of intestinal microflora following oral administration of this agent to Atlantic salmon (Salmo salar L.) smolts in a marine environment (original) (raw)
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Fish feed as a source of oxytetracycline-resistant bacteria in the sediments under fish farms
Aquaculture, 1995
Concentrations of oxytetracycline and the frequency of oxytetracycline resistance in the environmental microflora were monitored following the therapeutic use of this agent at a marine fish farm. 529 kg of oxytetracycline were administered over a 24 day period at an average of 1.4 kg per cage per day. Three days after the end of the therapy 4.6 f 3.7 pg/g oxytetracycline were detected in the sediments and the frequency of resistance in the sediment microflora was 9.0+ 5.3%. A rise in the frequency of resistance in this flora to 26 k 8.7% occurred 24 days after the therapy. This rise was not associated with any increase in the concentrations of oxytetracycline in the sediment. At this time the frequency of resistance in the flora isolated from mussels suspended above the sediments (36 + 8.5%) was significantly (P=O.O05) higher than that present in the sediment flora. The feed used on the farm 24 days after the end of therapy was shown to contain 4.6 X lo4 oxytetracycline-resistant cfu/g. The distribution of phenotypic groups in the oxytetracycline-resistant flora in this feed and in the sediments during the peak in resistance were compared with those from other marine environments. These data demonstrated that resistant flora in feed can, under certain circumstances, significantly contribute to the resistant flora detected in sediments under fish cages. 0001895S@bodkin,ucgie 0044~8486/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIOO44-8486(94)00330-O J. Kerry et al. /Aquaculture 131(1995)
Aquaculture, 1996
The concentrations of oxytetracycline and the frequencies of oxytetracycline resistant microorganisms were determined in 11 samples taken from the sediments in the vicinity of a block of fish cages at a marine salmon farm. The cage block contained IO tonnes of Atlantic salmon smolts and a total of 20 kg of oxytetracycline were administered during the I2 day treatment. Samples cores were collected by divers 5 days after the end of the period of therapy and the top 2 cm of each core was analysed. HPLC analysis was able to quantify the oxytetracycline concentrations in three of the six samples taken directly under the cage block. The mean concentration under the cage was between 0.65 and 1.2 pg gg ' (n = 6) depending on the values attributed to samples where the concentrations were below the level of quantitation (I .2 /lg gP '1. In the five samples taken from locations not directly under the cage block oxytetracycline was only detected in the sample taken adjacent to, and down current from, the cage block. This sample was collected 10 m to the west of the cage block and contained 4.2 pg g-' oxytetracycline. These data indicate that oxytetracycline was confined to an area of the sediment which was smaller in extent than the area of the cage block itself.
In India antibiotics are frequently used for preventing and controlling bacterial pathogens in carp aquaculture system, yet no studies have been performed to evaluate the ecological impact of its intensive and prolonged use. In this work the frequency of oxytetracycline-resistant bacteria from water, palletized feed and different life stages of fish from Indian freshwater carp aquaculture system as well as the level of resistance of selected strains was investigated. Viable as well as antibiotic-resistant bacterial counts were performed by spread plate method in culture media supplemented with the oxytetracycline. Sixty two resistant Gram negative isolates which represented the oxytetracycline-resistant bacterial population, were randomly selected on nutrient agar supplemented with oxytetracycline (50µg/ml) from carp farms and feed pellet samples. Among these bacterial isolates Flavobacterium (21%), Alcaligenes (14.5%), Aeromonas (11%), Pseudomonas (10%) and Enterobacteriace (19%) were the most frequent. The Escherichia, Serratia, Citrobacter, Enterobacter, Shigella and Proteus from Enterobacteriace were recovered. Twelve isolates of oxytetracycline resistant bacteria were mainly dominated in adult fishes by the genus Flavobacterium (23%) and Enterobacteriace(41%). Selected strains exhibited high levels of oxytetracycline resistance with minimum inhibitory concentrations (MICs) ranging from 50 to 600µg/ml.This study shows the presence of an important population of oxytetracycline-resistant bacteria in the microflora of Indian carp aquaculture farms. Therefore the environment of these farms might play important roles as reservoirs of bacteria carrying genetic determinants for high level tetracycline resistance, prompting an important risk to public health.
Problems of antibiotic resistance associated with oxytetracycline use in aquaculture: A review
Journal of entomology and zoology studies, 2020
Aquaculture is one of the fastest-growing industries in the world which has led to the intensification of fish farming methods to meet the global demands of fish production. To prevent and treat diseases that occur in aquaculture, antibiotics are being widely applied especially in developing countries, to forestall bacterial infections resulting from sanitary shortcomings in fish rearing. Antibiotics are mixed with feed and feed ingredients and are fed to fish to enhance their growth and ultimately boost up production. Oxytetracycline (OTC) is a tetracycline broad-spectrum antibiotic being widely used in aquaculture as a therapeutic and prophylactic agent ever since it was first approved by USFDA for use in finfish aquaculture. The indiscriminate use of oxytetracycline has led to a lot of problems such as the emergence of antibiotic‐resistant bacteria in aquaculture environments which in turn transfer these resistance factors to bacteria of terrestrial animals and human pathogens. M...
The fate of oxytetracycline in the marine environment of a salmon cage farm
2001
This paper gives a summary of previously published results of studies on the dispersal of oxytetracycline from the vicinity of a typical salmon farm. These studies showed the environmental impact of occasional treatments to be negligible. Concentrations of oxytetracycline (OTC) were measured in the benthic sediments and in mussel Mytilus edulis sampled in the vicinity of an inshore salmon farm on the west coast of Ireland. Concentrations between 1.0 µg/g and 14.7 µg/g were observed in sediments within 120 m from the farm. Concentrations declined exponentially with time, reaching low levels after 32 days and reduced to traces at 66 days. The highest concentrations were observed in the top 2 cm of sediment, falling to trace levels at a depth of 10 cm. The half-life of OTC persistence in mussels was found to be approximately 2 days. Residues in unpolluted sediment beneath the cages were never present in high concentrations and were flushed out rapidly. In the presence of excessive quantities of unconsumed food pellets on the seabed and in anoxic sediment, the persistence of OTC was significantly prolonged. Monitoring the quality of the sediment could therefore provide adequate indication of any risk of accumulation of antibiotic, without the need for elaborate chemical analyses. Residues in sediment, invertebrates and salmon could account for not more than 1.3% of total input of OTC. It was concluded that the antibiotic was very rapidly dispersed in the environment and its use in salmon therapy posed no material risk to human or environmental health. Coyne et al. The fate of oxytetracycline in the marine environment of a salmon cage farm _________________________________________________________________________________________________________ iii CONTENTS INTRODUCTION 1 Disease control 1 Control of chemical treatment 2 Chemotherapeutants in the environment 2 MATERIALS AND METHODS 5 The farm site 5 Sampling methods 5 Chemical analysis 8 Calculations of half-life of persistence 8 RESULTS 9
Animals
The extensive use of antibiotics is evident in most of the livestock and aquaculture management for inhibiting pathogen infection. Korean aquaculture depends on the usage of oxy-tetracycline for growing rainbow trout. Hence, this study was conducted to evaluate the changes in gut bacterial community profiles of rainbow trout exposed to oxy-tetracycline and predict the metabolic functioning of the bacterial community. The gut bacterial community composition of oxy-tetracycline treated fish was assessed by amplicon sequencing targeting the 16S rRNA gene of bacteria and comparing with the control group that did not receive any antibiotic. The principle coordinate analysis and non-metric multidimensional scaling analysis had shown two distinct clusters that implies the changes in community composition. In phyla level, the relative abundances of Tenericutes and Firmicutes were observed to be significantly higher in oxy-tetracycline treated fish compared to the control. Furthermore, the p...
Effect of Oxytetracycline on bacterial load of Labeorohita (Rohu) fish in culture pond
2014
The study was aimed to outline the anti biogram profiling of oxytetracycline against usual ecological bacterial flora of culture ponds of L. rohita. After applying pelleted feeds treated with oxytetracycline (OTC) at 2gm/kg the physicochemical parameters of water like temperature, pH, dissolved oxygen, alkalinity, ammonia and nitrate were recorded weekly: 28.99 to 31.09°C, 7.58-7.95 ppm, 5.36-5.86 mg/L, 86.31-111.99 mg/L, 0.20-0.30 mg/L and 0.11-0.17 mg/L, respectively. The total viable counts of bacteria were found 4.9±1.03×10 3 -5.75±1.0×10 3 cfu/mL in pond water, 5.62±1.0×10 7 -6.60±1.02×10 7 cfu/g in sediments, 6.77±1.0×10 6 -7.57±1.0×10 6 cfu/g in gills, 6.02±1.02×10 7 -8.32±1.0×10 7 cfu/g in gut of L. rohita in control ponds. After OTC treatment the total viable count of bacteria ranged from 3.1±1.19×10 3 -3.1±1.20×10 3 cfu/mL in water, 3.1±1.13×10 6 -4.27±1.10×10 6 cfu/g in sediment, 2.82±1.25×10 5 -3.09±1.19×10 5 cfu/g gill, 2.69±1.12×10 6 -4.68±1.12×10 6 cfu/g in guts of L. rohita respectively, indicating reduction of overall bacterial load below 1 log in sediment, gills and guts of L. Rohita significantly (P<0.005).
Marine pollution bulletin, 2008
A micro-dilution technique with changes in optical density (OD) used to measure bacterial growth over 72 h in culture media containing 0, 5, 10, 20, 40, 80 and 160 microg OTC (oxytetracycline)ml(-1) was applied to determine growth inhibition (GI) in mixed bacterial strains cultured from samples of marine sediments and salmon feed pellets. Growth of control cultures (Aeromonas salmonicida) was inhibited at all OTC concentrations. Some feed pellet samples and under-cage sediments from salmon aquaculture sites in the Bay of Fundy showed GI up to > or = 160 microg OTCml(-1). Lower values (40 to 80 microg OTC ml(-1)) occurred in subsurface (5-18 cm) sediments, > 100 m from salmon pens and adjacent to sewage outfalls in Halifax Harbour. GI values < 20 microg OTC ml(-1) in sediment from reference locations in Halifax Harbour and mussel aquaculture sites are considered to reflect natural background levels for OTC resistance.